The present invention is directed toward testing of specimens, and particularly toward an apparatus and method for properly adding fluids such as reagents during the processing of specimens for testing.
Testing sample biological specimens is commonly done, for example, to check for the presence of an item of interest, which item may be or include all or portions of a specific region of DNA, RNA, or fragments thereof, complements, peptides, polypeptides, enzymes, prions, proteins, messenger RNA, transfer RNA, mitochondrial RNA or DNA, antibodies, antigens, allergens, parts of biological entities such as cells, virons or the like, surface proteins, functional equivalents of the above, etc. Specimens such as a patient's body fluids (e.g., serum, whole blood, urine, swabs, plasma, cerebra-spinal fluid, lymph fluids, tissue solids) can be analyzed using a number of different tests to provide information about a patient's health.
In such testing, it is imperative that the specimens be handled in a manner which prevents contaminants from being introduced to the specimens, whether from the outside environment or between specimens. For example, where the HIV virus from one specimen is inadvertently allowed to contaminate the specimen of a different patient, the resulting false positive test result could potentially have catastrophic psychological effect on the patient, even should subsequent testing later discover the error. Moreover, since such testing is highly sensitive, even the smallest amounts of contamination can cause erroneous test results. Simply put, it is imperative that the specimens be properly handled.
In such sophisticated testing, it is also imperative that the various reagents which may be used in the testing be properly handled as well, not only to avoid contaminants but also to ensure that the proper reagent in proper quantities is used at appropriate times.
Commonly, such testing is accomplished using automated devices which handle multiple specimens and fluids (typically, reagents). Such automated devices typically will use sets of pipettes to move various fluids between their original containers (usually receptacles such as open topped tubes) and containers in which the specimens are to be processed. For example, a set of 8 specimens may be contained in 8 tubes or other receptacles loaded in a rack on the device, and a head carrying 8 pipettes will through programmed motion move the pipettes into those 8 tubes, where a vacuum will be applied to extract a selected amount of each specimen from its tube into the pipettes. The head will then retract the pipettes from the tubes and move over to another set of tubes located at a processing station, depositing the extracted amounts of each specimen from the pipettes into sets of testing tubes.
At the processing station of such automated devices, the specimens are variously handled according to the purpose of the testing (e.g., incubated, prepared, lysed, eluted, analyzed, read, etc.). For example, the specimens may be prepared for analyzing, as for example by separating DNA or RNA from the specimen. The specimens may also or alternatively be analyzed. Commonly, such processes involve the addition of various fluids (typically reagents) to the specimen in each tube. For example, in a first step, a reagent may be added to each of the tubes to wash the specimens, and second and third (and more) reagents may be added to the specimens in the course of carrying out other processes to, for example, unbind and/or separate the DNA or RNA of interest allow so that it may be extracted from the specimen in each tube for subsequent testing. Similar processes, in which the same or different reagents are added to the tubes, may also occur after the specimen has been prepared as a part of the analyzing of the prepared specimens.
The handling of the reagents and other fluids can, with such automated devices, be problematic. Though the reagents may be automatically moved from receptacles to the specimen containing tubes in the processing station by use of the head and pipettes such as noted, it is in the first instance necessary to load the appropriate reagent into the appropriate receptacle on the device in order to ensure that the head and pipettes are adding the appropriate reagent to the appropriate specimen containing tube at the appropriate time in the process. Further, it should be recognized that it is necessary for the receptacles to be readily cleaned, whether to remove possible contaminants or to permit use of different fluids in connection with different processes. As a result of such requirements, the receptacles are typically readily removable from the apparatus for such action.
Heretofore, loading the appropriate reagent into the appropriate receptacle has been accomplished in several different ways. In one such procedure, the individual who is controlling the device manually measures and adds the reagents to receptacles, and then places those receptacles on the device. In another such procedure, the loading of reagents is automatically accomplished by the device itself, which uses some transfer apparatus (such as a head and pipette(s) as previously described) to move the reagents from bulk supplies of the reagents provided with the device.
However, as already noted, either of the above procedures can be problematic. For example, manually adding the reagents can introduce human error, whether erroneously preparing the reagent, adding reagents to the wrong receptacles, or even mounting the receptacle incorrectly on the device. In the latter case, even if the correct reagents are loaded in the correct amounts, they will be at the wrong location on the device so that when the head and pipettes automatically draw a reagent for use at a certain step of the processing, it may well be the wrong reagent, or there could be no reagent of any kind where the head and pipettes go to extract it. Further, while such errors may be reduced using the second procedure (in which the device itself loads reagents from bulk supplies), the bulk supplies can themselves take up more room than is desirable for the device. Further, allowing this process to be accomplished by the device will, naturally, tie up the device while it carries out those steps. Tying up the device can reduce the amount of tests which are performed during a given day, and thereby either delay the completion of tests or require significant additional investment of capital for additional devices to allow for a desired testing capacity level.
The present invention is directed to overcoming one or more of the problems as set forth above.